Current-varying device



y 1966 E. E. FAIRBANKS CURRENT-VARYING DEVICE Filed Nov. 5. 1964 7 4a 49 5o 27 5 Sheets-Sheet 2 /III/ lHl I I A AI/I I T I Ill/I INVENTOR 51/5/2/ r21 4 AQEA/VKS ,4

TTO/ /VEXS United States Patent 3,262,081 CURRENT-VARYING DEVIC Everitt E. Fairbanks, Pacoima, Calif. Filed Nov. 3, 1964, Ser. No. 408,700

8 Claims. (Cl. 338-155) This invention relates to current controlling .levices adaptable for use as otentiometers, variable-resistance, stepping switches, or analogous devices, and is a con tinuation-in-par-t of my previously filed application for Current-Varying Device, filed November 19, 1963, Serial No. 324,628, now abandoned.

Included in the objects of this invention are:

First, to provide a current controlling device which uses a uniquely arranged wobble ring as the moving contactor, and a unique magnetic circuit for moving the wobble ring.

Second, to provide a current controlling device wherein the magnetic circuit maintains a relatively high contact pressure between the moving contactor of the wobble ring and the fixed contact means of the device; however, the wobble ring and magnetic circuit maintains a rolling contact as distinguished from a sliding contact, so that the force required to move the wobble ring is minimized.

Third, to provide a current controlling device which lends itself to miniaturization and wherein an extremely weak driving force produced by a sensing means such as a gyroscope, may be employed through the current controlling device to operate responsive mechanism requiring relatively high current.

Fourth, to provide a current controlling device which may be hermetically sealed.

Fifth, to provide a current controlling device which, in one embodiment, is particularly adapted for the control of an air conditioning system, a single device being operable to control both the heating and the cooling components of the system.

With the above and other objects in view, as may appear hereinafter, reference is directed to the accompanying drawings in which:

FIGURE 1 is a transverse side of the current-varying device as a potentiometer;

FIGURE 2 is a side view thereof;

FIGURE 3 is an enlarged, sectional view taken through 3-3 of FIGURE 2;

FIGURE 4 is a transverse, sectional view taken through 44 of FIGURE 3 with portions broken away to show the underlying structure;

FIGURE 5 is a fragmentary, transverse sectional view showing the current-varying device as a stepping switch.

FIGURE 6 is a longitudinal sectional view of a modified form of the current-controlling device taken through 66 of FIGURE 7;

FIGURE 7 is a longitudinal sectional view thereof taken through 7--7 of FIGURE 6;

FIGURE 8 is a transverse sectional view thereof taken through 88 of FIGURE 6;

FIGURE 9 is another transverse sectional view thereof taken through 9-9 of FIGURE 6;

FIGURE 10 is a fragmentary sectional view taken through 1010 of FIGURE 8;

FIGURE 11 is a fragmentary sectional view taken through 11-11 of FIGURE 9;

FIGURE 12 is a longitudinal sectional view showing a further modified form of the current controlling device;

FIGURE 13 is an enlarged fragmentary sectional view of a wobble member and contactor adapted to the various modifications of the current controlling device;

FIGURE 14 is an enlarged longitudinal sectional view of a further modified current controlling device which is particularly suitable for miniaturization;

FIGURE 15 is a further enlarged sectional view of the contactor portion of the wobble member employed in the construction shown in FIGURE 14.

Reference is first directed to FIGURES 1 through4 wherein the current controlling device is embodied as a potentiometer. The potentiometer includes a cup-shaped case 1, the open upper end of which is closed by a cover 2 in the form of a shallow inverted cup. The rim of the cover 2 fits telescopically in the case 1, and clamped between the case and the cover 2 is a sealing diaphragm 3 so as to form with the case 1 a sealed compartment 4.

Secured within the case 1 is an annular resistance coil 5 having terminals 6 which extend axially or radially through the case 1. Also secured in the case 1 is a central or axially disposed post 7, screw-threaded at its outer end, and also forming a terminal. Centered in the diaphragm 3 is a pivot pin 8 having a pointed end confronting the central post 7.

A wobble disk 9 formed of sheet metal is interposed between the pivot pin 8 and the post 7. At its center the wobble disk 9 is provided with a conical pivot recess 10, or it may be provided with a jewel hearing which is engaged by a pointed lower end of the pivot pin 8. The wobble disk 9 is held in engagement with the pivot pin 8 by means of a spring 11 which surrounds the central post 7, and which may serve as a conductor. Alternatively, a highly flexible wire may extend from the wobble disk 9 to the post 7 or other terminal.

Adjacent the periphery of the wobble disk 9 its underside is provided with an annular contact rim 12. It upper side is provided with a magnet ring 13 which may be in the form of a ferrite coating, or may be a magnetic ring bonded to the wobble disk 9 by an adhesive,

The upper end of the pivot pin 8 is provided with a pivot recess 14, which may also be a jewel bearing, and serves as a journal for the lower end of a shaft 15. The shaft 15 extends through a jewel bearing 16 provided in the cover 2. Extending laterally from the lower end of the shaft 15 adjacent the pivot pin 8, is a diameterically balanced pair of arms 17, one of which carries at its extremity a movable pole piece 18 disposed as close as possible to the diaphragm 3.

Fitted within the cover 2 is an annular, fixed pole piece 19 having an axially extending, annular portion 20 and a radially, inwardly extending portion 21. An annular magnet 22 having axial pole extremities is set within the fixed pole piece 19 in contact with the radially, inwardly extending portion 21 thereof. The other extremity of the magnet 22 is disposed in close, contiguous relation with the movable pole piece 18.

Operation of the current controlling device is an follows:

As shown in FIGURE 3 a magnetic circuit is formed which passes through the movable pole piece 18, the ferrite coating or magnetic ring 13, and through the fixed pole piece 19 back to the magnet 22. The effect of this magnetic circuit is to draw one side of the wobble disk 9 underlying the movable pole piece 18 toward the sealing diaphragm 3, so as to force the diametrically opposite side of the wobble disk 9 toward the coil 5 and cause the corresponding portion of the contact rim 12 to engage the coil 5. Rotation of the shaft 15 and corresponding rotation of the pole piece 18 causes a corresponding rolling, but not sliding, contact between the rim 12 and the coil 5.

It should be noted that the relatively large, fixed pole piece 19 and its substantial magnetic field tilts the wobble disk 9 with substantial force, so as tomake good contact between the wobble disk 8 and the coil '5. This.

substantial force is controlled, however, by the movable pole piece 18 of minimal mass which merely changes the location at which the force is applied.

While the wobble disk 8 is not restrained against rotation about the axis through the coil 5, there is no appreciable force tending to produce rotation; consequently, the wobble disk 9 merely wobbles relative to its support as the pole piece 18 is rotated.

Inasmuch as there is a minimal gap between the movable pole piece 18 and the diaphragm 3 and magnet 22, the pole piece is freely rotatable. This fact together with the jewel mounting requires a minimum of rotating force; thus rendering the current controlling device suitable for direct coupling to the output shaft of a gyroscope or other sensing device of limited torque output.

In view of the fact that the coil compartment 4 may be sealed, artificial atmosphere may be maintained within the compartment 4.

Reference is now directed to FIGURE 5, in which a series of contacts 23 is substituted for the coil to serve as steps of a stepped resistance or of a stepping switch.

Reference is now directed to FIGURES 6 through 11. In this construction the entire magnetic circuit is within the same compartment as the wobble plate and is so arranged as to provide increased contact pressure. This construction includes a pair of complementary housing members 25 and 26 having overlapping portions 27 disposed in a diametrica-l plane. The housing members define a spherical zone 28 the axial sides of which communicate with a top recess 29 and a bottom recess 30.

Centered in the housings is a cylindrical permanent magnet 31 fitted with a non-magnetic sleeve 32. The opposite sides of the axial ends of the sleeve lying in the region of the overlapping portions 27 of the housings are held in notches 33 formed at the junctures between the spherical zone 28 and recesses 29 and 30 as shown in FIGURE 7.

The axial ends of the magnet 31 are covered by fixed pole plates 34 in which are centered bearings 35. The bearings journal movable pole plates 36 about the axis of the magnet which is also the common axis of the housing members 25 and 26. The pole plates 36 are provided with diametrically oppositely disposed pole tips 37 which project into the axial ends of the spherical zone 28. Spacer screws 38 secure the pole plates 36 together for movement as a unit.

Loosely disposed within the spherical zone 28 and surrounding the sleeve 32 is a wobble ring 39 formed of magnetic material. The wobble ring is dimensioned so that when the wobble ring is tilted, diametrically opposite portions thereof are located at opposite axial ends of the spherical zone and confront the pole tips 37. The pole tips are beveled so that they are parallel to the faces of the Wobble ring. The wobble ring 39 carries an outwardly extending contactor ring 40.

The housing members 25 and 26 are provided arcuate ledges 41 'and 42, respectively, located at opposite axial ends of the spherical zone 28 and at diametrically opposite sides thereof. When diametrically opposite portions of the wobble ring 39 confront the pole tips 37, the corresponding portions of the contactor ring 46 bear against the ledges 41 and 42. As the pole tips rotate about their common axis, the contactor ring 40 rotates on the ledges in firm contact therewith.

The ledges 41 and 42 may be provided with various types of contact elements depending upon the use intended for the current controlling device. For example, a pair of arcuate potentiometer units 43 each encased in a shell 44 may be fitted in arcuate slots formed in the housing member 25 and held in place by set screws 45. Similarly, the housing member 26 may be provided with arcuate slots which receive arcuate contact bars 46. In place of, or set into the contact bars, is a pair of switch operating pins 47 which, on rocking movement of the contactor ring may operate switches, not shown, located outside the housing member 26.

Movement of the pole plates 36 may be accomplished in various Ways depending upon the purpose of the current controlling device. For example, a shaft may extend axially through the housing members; or, as illustrated, a solenoid drive may be provided. One of the movable pole plates 36 is provided with an armature boss 48 which projects into the recess 29. A spring 49 is wrapped about a central post 56 and is provided with end portions which engage the armature boss 48 and a suitable anchoring surface so as to yieldably maintain the armature boss in a neutral or other predetermined position.

Fitted within the margins of the recess 29 is a U-shaped solenoid core 51 terminating in pole pieces 52 confronting opposite sides of the armature boss 48. A solenoid coil 53 is provided for the core 51.

The construction shown in FIGURES 6 through 11 is particularly adapted for control of air conditioning means involving both heating and cooling components, wherein one potentiometer controls the heating component and the other controls the cooling component. A conventional sensing means, not shown, controls the voltage in the solenoid coil 52 so as to bias the armature boss 48 toward one or the other of the pole pieces 52. The appropriate air conditioning component may be turned on by completion of a circuit through a contact bar 46 and the corresponding potentiometer 43 and then regulated by the potentiometer as the contactor ring moves thereover. Alternatively, switches, not shown, operated by the pins 47 may initiate operation of the appropriate air conditioning component.

It will be observed that the magnetic circuit through the magnet 31, fixed pole plates 34, movable pole plates 36, pole tips 37 and wobble ring 39, require only minimal air gaps between the pole plates and between the pole tips and wobble ring and a firm contact pressure is maintained between the contactor ring 40 and the contact means it engages. However, the contactor ring maintains a rolling contact, and no change in air gap spacing occurs, thus the force required to turn the movable pole plates 36 is reduced to a minimum.

Reference is now directed to FIGURE 12. In this construction the magnetic circuit is similar to that shown in FIGURES 6 through 11; however, in this case, all of the componets of the magnetic circuit rotate, thus eliminating one pair of air gaps.

As shown in FIGURE 12, a pair of complementary housing members 54 and 55 are provided which are joined diametrically by overlapping portions 56. The two housing members define a central spherical zone 57 and end recesses 58 and 59. In this construction, the range of movement may be essentially a complete circle; thus, the axial ends of the spherical zone 57 defines annular ledges 6t and 61.

Centered within the housing members is a permanent magnet 62 fitted within a non-magnetic sleeve 63. Secured to opposite axial ends of the magnet by screws 64 extending into the sleeve 63 is a pair of pole plates 65. A pair of axially aligned bearings 66 interposed between the pole plates and the housings 54 and 55 journal the pole plates, magnet and sleeve as a unit.

The pole plates 65 are provided with pole tips 67 similar to the pole tips 37. The pole tips 67 are directed toward the axial ends of the spherical zone 57. Loosely received in the spherical zone is a wobble ring 68, similar to the wobble ring 39 of magnetic material. Projecting radially from the wobble ring 68 is a contact ring 69 which, as shown in FIGURE 13, may comprise a plurality of thin laminations so that the ring may flex slightly, to effect a slight contact wipe for better electrical connections. The wobble ring and contact ring are held in an angular and tilted position with diametrically opposite sides of the contact ring engaging the axially opposite ledges 6t! and 61 by the attraction of the wobble ring 68 to the pole tips 67.

The ledges 66 and 61 are provided with suitable contact means such as shown in FIGURES l0 and 11, or with a single potentiometer coil and mating contact bar; or with a plurality of contacts such as indicated in FIG- URE 5, forming the steps of potentiometer or other resistance, reactance or switching means, depending upon the intended use of the current controlling device. The arcuate extent of the potentiometer or the like may approach a full circle.

The wobble rings 39 and 68 are held in operating position magnetically and normally clear the ledges 41, 42 and 60, 61. However, to prevent dislodgement in the event of mechanical impact or the like, the ledges are provided with small peripheral rims 70 which constrain the wobble rings. Also, the spherical walls of the zones 28 and 57 clear the contactor rings 40 and 69 only a slight distance to form an additional constraining means.

The magnet assembly may be rotated by a gear drive including a driven gear 71 formed. integral with or secured to one of the pole plates 65 and a driving gear 72 mounted on a stem 73 extending through a bearing 74 provided in the housing member 54. The gear drive is operated by a suitable sensing means, not shown.

Reference is now directed to FIGURES 14 and 15. In this construction the magnetic circuit is incorporated in the housing. More specifically, an annular magnet 75 is covered at its axial ends by fixed pole plates 76. Each pole plate is provided with a centered opening which receives a bearing bushing 77. In the lower bearing bushing 77 is fitted a thrust bearing 78, preferably of the jewel type. The upper bearing bushing receives a radial hearing 79. A shaft 80 having a pointed end resting on the thrust bearing 78 extends between the bearings and protrudes from the upper bushing for engagement by a suitable drive means.

Each fixed pole plate 76 is provided with an inwardly directed annular pole rim 81 surrounding their bushing openings. Mounted on the shaft 80 is a pair of movable pole arms 82 extending in radially opposite directions and terminating in close confronting relation to the pole rims 81. At their sides opposite from the pole rims 81 the pole arms 82 are provided with pole tips 83.

Loosely received in the chamber formed by the magnet and fixed pole plates is a wobble ring 84, the radially inner portion of the wobble ring confronting the pole tips 83. The wobble ring 84 extends radially outwardly from the pole tips 83 and is provided with annular grooves 85 at its axially opposite sides. The surfaces of the grooves may be plated or otherwise coated with a highly conductive coating, forming a contactor surface 86.

Surrounding one of the pole rims 81 is an annular potentiometer coil 87 wrapped about a core of insulating material. An annular contact ring 88 surrounds the coil 87 and ring 88 may be held in place by an adhesive 89. The potentiometer coil and contact ring are engaged by the contactor surfaces 86 of the grooves 85.

The wobble ring 84' is normally held in place by its attraction to the pole tips 8?: and by interengagement of the grooves 85 with the coil 87 and ring 88. However, in addition, a pair of complementary rings 90 of nonmagnetic material may line the magnet 75 and define a spherical wall closely confronting the periphery of the wobble ring.

Operation of the embodiments shown in FIGURES 12 through 15 is essentially the same as the construction shown in FIGURES 6 through 11. The magnetic circuit maintains the contactor ring 69, or contactor surfaces 86 in firm contact with the potentiometer or other contact means while permitting a rolling engagement with minimal friction.

With respect to the construction shown in FIGURES 6 through 11, with particular reference to FIGURE 10, the axial movement of the pins 47 is proportional to the rocking movement of the wobble ring. This axial or linear movement may be used to operate any of several conventional devices, the output signal of which is proportional to the axial movement. For example, adjustment of the iron core in a radio frequency inductor employed in a tuned circuit; control of small proportioning valves, etc.

ANTHONY BARTIS, Examiner. a 1! While particular embodiments of this invention have been shown and described, it is not intended to limit the same to the details of the constructions set forth, but instead, the invention embraces changes, modifications and equivalents of the various parts and their relationships as come within the purview of the appended claims.

What is claimed is:

1. A control means, comprising:

a. a housing defining a chamber having a central axis and axially displaced circular surfaces facing toward each other;

. a wobble ring within said chamber and including a circular magnetic element, and a concentric means for engaging said surfaces at diametrically opposite sides;

c. magnetic circuit means including a magnet, 21 pair of diametrically disposed and axially displaced pole tips at opposite ends of said magnet positioned to tilt said wobble ring to cause one side of said engaging means to roll on one of said circular surfaces and the diametrically opposite side of said engaging means to roll on the other of said circular surfaces;

d. and means for turning said pole tips about the axis of said housing to roll said engaging means progressively on said circular surfaces.

. A control means as set forth in claim 1, wherein:

a. said magnet is fixed, centered in said cavity and surrounded by said wobble ring, and said pole tips extend from rotatable pole plates at opposite axial ends of said magnet.

. A control means as set forth in claim 1, wherein:

a. said magnet is rotatable, centered in said cavity and surrounded by said wobble ring and said pole tips extend from pole plates overlying the axial ends of said magnet and secured thereto for rotation therewith.

4. A control means as set forth in claim 1, wherein:

a. said magnet is annular and surrounds said wobble ring and magnetic disks cover the ends of said magnet, said magnetic disks axially overlapping the magnetic element of said wobble ring, said magnet and magnetic disks forming portions of said housing;

b. a shaft is journalled about the axis of said housing;

c. and said pole tips are supported from said shaft and are interposed between said wobble disk and said magnetic disks.

5. A control means as set forth in claim 1, wherein:

a. axially extending linearly movable elements protrude from at least one of said circular surfaces for engagement by said engaging means, thereby to move linearly in proportion to rolling movement of said engaging means.

6. A control means as set forth in claim 1, wherein:

a. a resistance element constitutes at least a portion of one of said surfaces.

'7. A control means as set forth in claiml, wherein:

a. switch actuating elements protrude from at least one of said surfaces for engagement by rolling movement by said engaging means.

8. A control means as set forth in claim 1, wherein:

a. said turning means includes an armature movable with said pole tips, an electro magnet having poles confronting opposite sides of said armature, and a solenoid for attracting said armature toward either of said poles thereby to effect corresponding movement of said pole tips and wobble ring.

References Cited by the Examiner UNITED STATES PATENTS RICHARD M. WOOD, Primary Examiner. 

1. A CONTROL MEANS, COMPRISING: A. A HOUSING DEFINING A CHAMBER HAVING A CENTRAL AXIS AND AXIALLY DISPLACED CIRCULAR SURFACES FACING TOWARD EACH OTHER; B. A WOBBLE RING WITHIN SAID CHAMBER AND INCLUDING A CIRCULAR MAGNETIC ELEMENT, AND A CONCENTRIC MEANS FOR ENGAGING SAID SURFACES AT DIAMETRICALLY OPPOSITE SIDES; C. MAGNETIC CIRCUIT MEANS INCLUDING A MAGNET, A PAIR OF DIAMETRICALLY DISPOSED AND AXIALLY DISPLACED POLE TIPS AT OPPOSITE ENDS OF SAID MAGNETIC POSITIONED TO TILT SAID WOBBLE RING TO CAUSE ONE SIDE OF SAID ENGAGING MEANS TO ROLL ON ONE OF SAID CIRCULAR SURFACES AND THE DIAMETRICALLY OPPOSITE SIDE OF SAID ENGAGING MEANS TO ROLL ON THE OTHER OF SAID CIRCULAR SURFACES; D. AND MEANS FOR TURNING SAID POLE TIPS ABOUT THE AXIS OF SAID HOUSING TO ROLL SAID ENGAGING MEANS PROGRESSIVELY ON SAID CIRCULAR SURFACES. 